This invention relates to the field of load transmission devices. More particularly, this invention relates to a self-aligning load transmission post for use with a plurality of bellows or other devices in an environment where there are critical requirements for the direction and location in which a load is imposed.
Although not limited thereto in its utility, this invention is particularly intended to be an improvement in the construction of the mechanical torque wrench with hydraulic readout described in U.S. Pat. No. 3,683,686 assigned to the assignee of the present invention. Reference is hereby made to U.S. Pat. No. 3,683,686 for incorporation herein for a full understanding of the environment and details thereof in which the preferred embodiment of this invention will be described.
The torque wrench of U.S. Pat. No. 3,683,686 has a hydraulic readout system to obtain measurements of the torque being applied. That hydraulic readout system employs two hydraulic load cells, in the form of bellows, and a Bourdon gauge interconnected by hydraulic tubing, those elements being hermetically sealed and filled with a non-compressible fluid. As torque is applied with the wrench, reaction forces equal to output torque of the wrench are imposed on the bellows and measured on the Bourdon gauge to provide an accurate measurement of the torque output of the wrench.
Each bellows is mounted between a pair of opposed posts, and the reaction forces are applied to the bellows through these posts. Equalization of the loads on the bellows is critical for accurate readout of the torque load; and experience has shown that very close tolerances must be maintained on the alignment of the posts with each other and with the center line of the bellows to achieve this load equalization and accuracy in readout. While these tolerances can be realized, they increase the time and cost of manufacturing the wrench; and it has become highly desirable to find other ways of obtaining the desired load equalization.